l6 MAIXE AGRICULTURAL EXPJiRIMEXT STATION. I917. 



and those given above for Maine cattle in general is sufficiently 

 striking. This result does not mean at all that old bulls will 

 necessarily get better or more productive heifers than young 

 bulls. Evidence that this is not necessarily so is seen even in 

 the present table in the cases of Jacoba Irene, whose sire was 

 only one year old at the time of this service, and Eminent's 

 Bess, whose sire was only two years old. \A'hat the result 

 does mean is that those Jersey breeders zcho are breeding 

 zcorld's record animals in the great majority of cases are pro- 

 ducing those animals zvith tested sires, which they know from 

 actual previous experience are transmitting to their offspirng 

 high dairy ciualities. 



A graphic comparison of the facts as to age of sires of 

 Maine cattle in general and of this group of high producing 

 Jerseys is shown in Fig. i. The cross-hatched areas above 

 and below the four year line show in a striking way the pro- 

 portionate number of offspring sired by old and young bulls 

 in the two cases. 



BREED FROM TESTED SIRES. 



^ 10 



'^ 4 



65 * or WORLDS RECORD 

 JERSCr cows ARC SIRED BY 

 BULlS OVER 4 YEARS OLD 



40 50 (a /£? 



PER CENT or CALVES 



Fig. I. For further explanation see text. 



Similar data for Holsteins are given in Table XIL Here 

 we have 25 cows of outstanding productive merit as evidenced 

 by 12 month records. The arrangement of the table is the 

 same as ''n the case of Table XL 



